X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=rts%2FSchedule.c;h=375520d011327b8d7cb885b353394db5273d06be;hb=8cc74db64356bd332a11c73788c4108e2e3c5acd;hp=8bd42414b52f25a8342913738063f6d32c5fd6ab;hpb=d759c7231dde979ed2824bd39b2fdff24357d355;p=ghc-hetmet.git

diff --git a/rts/Schedule.c b/rts/Schedule.c
index 8bd4241..375520d 100644
--- a/rts/Schedule.c
+++ b/rts/Schedule.c
@@ -593,7 +593,19 @@ run_thread:
 
     dirtyTSO(t);
 
-    recent_activity = ACTIVITY_YES;
+#if defined(THREADED_RTS)
+    if (recent_activity == ACTIVITY_DONE_GC) {
+        // ACTIVITY_DONE_GC means we turned off the timer signal to
+        // conserve power (see #1623).  Re-enable it here.
+        nat prev;
+        prev = xchg(&recent_activity, ACTIVITY_YES);
+        if (prev == ACTIVITY_DONE_GC) {
+            startTimer();
+        }
+    } else {
+        recent_activity = ACTIVITY_YES;
+    }
+#endif
 
     switch (prev_what_next) {
 	
@@ -974,6 +986,8 @@ scheduleDetectDeadlock (Capability *cap, Task *task)
 	cap = scheduleDoGC (cap, task, rtsTrue/*force  major GC*/);
 
 	recent_activity = ACTIVITY_DONE_GC;
+        // disable timer signals (see #1623)
+        stopTimer();
 	
 	if ( !emptyRunQueue(cap) ) return;
 
@@ -2123,16 +2137,34 @@ forkProcess(HsStablePtr *entry
     // ToDo: for SMP, we should probably acquire *all* the capabilities
     cap = rts_lock();
     
+    // no funny business: hold locks while we fork, otherwise if some
+    // other thread is holding a lock when the fork happens, the data
+    // structure protected by the lock will forever be in an
+    // inconsistent state in the child.  See also #1391.
+    ACQUIRE_LOCK(&sched_mutex);
+    ACQUIRE_LOCK(&cap->lock);
+    ACQUIRE_LOCK(&cap->running_task->lock);
+
     pid = fork();
     
     if (pid) { // parent
 	
+        RELEASE_LOCK(&sched_mutex);
+        RELEASE_LOCK(&cap->lock);
+        RELEASE_LOCK(&cap->running_task->lock);
+
 	// just return the pid
 	rts_unlock(cap);
 	return pid;
 	
     } else { // child
 	
+#if defined(THREADED_RTS)
+        initMutex(&sched_mutex);
+        initMutex(&cap->lock);
+        initMutex(&cap->running_task->lock);
+#endif
+
 	// Now, all OS threads except the thread that forked are
 	// stopped.  We need to stop all Haskell threads, including
 	// those involved in foreign calls.  Also we need to delete
@@ -2170,6 +2202,9 @@ forkProcess(HsStablePtr *entry
 	ACQUIRE_LOCK(&sched_mutex);
 	for (task = all_tasks; task != NULL; task=task->all_link) {
 	    if (task != cap->running_task) {
+#if defined(THREADED_RTS)
+                initMutex(&task->lock); // see #1391
+#endif
 		discardTask(task);
 	    }
 	}
@@ -2185,6 +2220,7 @@ forkProcess(HsStablePtr *entry
 
         // On Unix, all timers are reset in the child, so we need to start
         // the timer again.
+        initTimer();
         startTimer();
 
 	cap = rts_evalStableIO(cap, entry, NULL);  // run the action
@@ -2531,6 +2567,7 @@ initScheduler(void)
 
   context_switch = 0;
   sched_state    = SCHED_RUNNING;
+  recent_activity = ACTIVITY_YES;
 
 #if defined(THREADED_RTS)
   /* Initialise the mutex and condition variables used by
@@ -3093,10 +3130,10 @@ findRetryFrameHelper (StgTSO *tso)
 	return CATCH_RETRY_FRAME;
       
     case CATCH_STM_FRAME: {
-        debugTrace(DEBUG_stm,
-		   "found CATCH_STM_FRAME at %p during retry", p);
         StgTRecHeader *trec = tso -> trec;
 	StgTRecHeader *outer = stmGetEnclosingTRec(trec);
+        debugTrace(DEBUG_stm,
+		   "found CATCH_STM_FRAME at %p during retry", p);
         debugTrace(DEBUG_stm, "trec=%p outer=%p", trec, outer);
 	stmAbortTransaction(tso -> cap, trec);
 	stmFreeAbortedTRec(tso -> cap, trec);